The PCA9665 serves as an interface between most standard parallel-bus microcontrollers/microprocessors and the serial I2C-bus and allows the parallel bus system to communicate bidirectionally with the I2C-bus. The PCA9665 can operate as a master or a slave and can be a transmitter or receiver. Communication with the I2C-bus is carried out on a Byte or Buffered mode using interrupt or polled handshake. The PCA9665 controls all the I2C-bus specific sequences, protocol, arbitration and timing with no external timing element required. The PCA9665 has the same footprint as the PCA9564 with additional features: